symlink support in devfs.

it only barely works so don't get too carried away..
I noticed that teh symlink is length 0..
I guess I'll fix that tomorrow..
it also sometimes panics with "cleaned vnode isn't" but it's not more
broken than it was before.. I really want to go over it with someone
who understands the lifecycle of a vnode better than I do..

terry?
kirk?
david?
john?

sys/miscfs/devfs/devfs_tree.c

@@ -2,7 +2,7 @@
 /*
  *  Written by Julian Elischer (julian@DIALix.oz.au)
  *
- *	$Header: /home/ncvs/src/sys/miscfs/devfs/devfs_tree.c,v 1.26 1996/07/24 21:22:36 phk Exp $
+ *	$Header: /home/ncvs/src/sys/miscfs/devfs/devfs_tree.c,v 1.27 1996/07/30 18:00:32 bde Exp $
  */
 
 #include "param.h"
@@ -157,25 +157,21 @@ dev_finddir(char *orig_path, dn_p dirnode, int create, dn_p *dn_pp)
 	* find the next segment of the name	*
 	\***************************************/
 	cp = name = path;
-	while((*cp != '/') && (*cp != 0))
+	while((*cp != '/') && (*cp != 0)) {
-	{
 		cp++;
 	}
 
 	/***********************************************\
 	* Check to see if it's the last component	*
 	\***********************************************/
-	if(*cp)
+	if(*cp) {
-	{
 		path = cp + 1;	/* path refers to the rest */
 		*cp = 0; 	/* name is now a separate string */
 		if(!(*path))
 		{
 			path = (char *)0; /* was trailing slash */
 		}
-	}
+	} else {
-	else
-	{
 		path = (char *)0;	/* no more to do */
 	}
 
@@ -183,13 +179,10 @@ dev_finddir(char *orig_path, dn_p dirnode, int create, dn_p *dn_pp)
 	* Start scanning along the linked list	*
 	\***************************************/
 	devnmp = dev_findname(dirnode,name);
-	if(devnmp)
+	if(devnmp) {	/* check it's a directory */
-	{	/* check it's a directory */
 		dnp = devnmp->dnp;
 		if(dnp->type != DEV_DIR) return ENOTDIR;
-	}
+	} else {
-	else
-	{
 		/***************************************\
 		* The required element does not exist	*
 		* So we will add it if asked to.	*
@@ -203,12 +196,9 @@ dev_finddir(char *orig_path, dn_p dirnode, int create, dn_p *dn_pp)
 		}
 		dnp = devnmp->dnp;
 	}
-	if(path)	/* decide whether to recurse more or return */
+	if(path) {	/* decide whether to recurse more or return */
-	{
 		return (dev_finddir(path,dnp,create,dn_pp));
-	}
+	} else {
-	else
-	{
 		*dn_pp = dnp;
 		return 0;
 	}
@@ -246,8 +236,7 @@ dev_add_name(char *name, dn_p dirnode, devnm_p back, dn_p dnp,
 	 * Allocate and fill out a new directory entry 
 	 */
 	if(!(devnmp = (devnm_p)malloc(sizeof(devnm_t),
-				M_DEVFSNAME, M_NOWAIT)))
+				M_DEVFSNAME, M_NOWAIT))) {
-	{
 		return ENOMEM;
 	}
 	bzero(devnmp,sizeof(devnm_t));
@@ -365,6 +354,10 @@ dev_add_node(int entrytype, union typeinfo *by, dn_p proto, dn_p *dn_pp)
 	{
 		return ENOMEM;
 	}
+	/*
+	 * If we have a proto, that means that we are duplicating some
+	 * other device, which can only happen if we are not at the back plane
+	 */
 	if(proto) {
 		/*  XXX should check that we are NOT copying a device node */
 		bcopy(proto, dnp, sizeof(devnode_t));
@@ -374,6 +367,9 @@ dev_add_node(int entrytype, union typeinfo *by, dn_p proto, dn_p *dn_pp)
 		dnp->vn = NULL;
 		dnp->len = 0;
 	} else {
+		/* 
+		 * We have no prototype, so start off with a clean slate
+		 */
 		bzero(dnp,sizeof(devnode_t));
 		dnp->type = entrytype;
 		TIMEVAL_TO_TIMESPEC(&time,&(dnp->ctime))
@@ -403,6 +399,26 @@ dev_add_node(int entrytype, union typeinfo *by, dn_p proto, dn_p *dn_pp)
 		dnp->ops = &devfs_vnodeop_p;
 		dnp->mode |= 0555;	/* default perms */
 		break;
+	case DEV_SLNK:
+		/*
+		 * As it's a symlink allocate and store the link info
+		 * Symlinks should only ever be created by the user,
+		 * so they are not on the back plane and should not be 
+		 * propogated forward.. a bit like directories in that way..
+		 * A symlink only exists on one plane and has it's own
+		 * node.. therefore we might be on any random plane.
+		 */
+		dnp->by.Slnk.name = malloc(by->Slnk.namelen+1,
+					M_DEVFSNODE, M_NOWAIT);
+		if (!dnp->by.Slnk.name) {
+			free(dnp,M_DEVFSNODE);
+			return ENOMEM;
+		}
+		strncpy(dnp->by.Slnk.name,by->Slnk.name,by->Slnk.namelen);
+		dnp->by.Slnk.namelen = by->Slnk.namelen;
+		dnp->ops = &devfs_vnodeop_p;
+		dnp->mode |= 0555;	/* default perms */
+		break;
 	/*******************************************************\
 	* The rest of these can't happen except in the back plane*
 	\*******************************************************/
@@ -461,6 +477,9 @@ devfs_dn_free(dn_p dnp)
 	if(--dnp->links <= 0 ) /* can be -1 for initial free, on error */
 	{
 		/*probably need to do other cleanups XXX */
+		if(dnp->type == DEV_SLNK) {
+			free(dnp->by.Slnk.name,M_DEVFSNODE);
+		}
 	        devfs_dropvnode(dnp);
 	        free (dnp, M_DEVFSNODE);
 	}
@@ -500,7 +519,8 @@ devfs_add_fronts(devnm_p parent,devnm_p child)
 	for (falias = parent->next_front; falias; falias = falias->next_front)
 	{
 		/*
-		 * If a Dir (XXX symlink too one day)
+		 * If a Dir (XXX symlink too one day?)
+		 * (...Nope, symlinks don't propogate..)
 		 * Make the node, using the original as a prototype)
 		 */
 		if(type == DEV_DIR) {
@@ -601,6 +621,7 @@ devfs_free_plane(struct devfsmount *devfs_mp_p)
 * Create and link in a new front element.. 			*
 * Parent can be 0 for a root node				*
 * Not presently usable to make a symlink XXX			*
+* (Ok, symlinks don't propogate)
 * recursively will create subnodes corresponding to equivalent	*
 * child nodes in the base level					*
 \***************************************************************/
@@ -703,7 +724,7 @@ dev_free_name(devnm_p devnmp)
 	 */
 	if(parent) /* if not fs root */
 	{
-		if( *devnmp->prevp = devnmp->next)/* yes, assign */
+		if( (*devnmp->prevp = devnmp->next) )/* yes, assign */
 		{
 			devnmp->next->prevp = devnmp->prevp;
 		}
@@ -721,9 +742,9 @@ dev_free_name(devnm_p devnmp)
 	 * from that..
 	 * Remember that we may not HAVE a backing node.
 	 */
-	if (back = devnmp->as.front.realthing) /* yes an assign */
+	if ( (back = devnmp->as.front.realthing) ) /* yes an assign */
 	{
-		if( *devnmp->prev_frontp = devnmp->next_front)/* yes, assign */
+		if((*devnmp->prev_frontp = devnmp->next_front))/* yes, assign */
 		{
 			devnmp->next_front->prev_frontp = devnmp->prev_frontp;
 		}
@@ -773,9 +794,12 @@ DBPRINT(("	vntodn "));
 		printf("No references! ");
 	}
 #endif
-	if((vn_p->v_type == VBAD) || (vn_p->v_type == VNON))
+	switch(vn_p->v_type) {
-	{
+	case VBAD:
-		printf("bad-type2 ");
+		printf("bad-type2 (VBAD)");
+		return(EINVAL);
+	case VNON:
+		printf("bad-type2 (VNON)");
 		return(EINVAL);
 	}
 	*dn_pp = (dn_p)vn_p->v_data;
@@ -888,6 +912,7 @@ DBPRINT(("(New vnode)"));
 		switch(dnp->type)
 		{
 		case	DEV_SLNK:
+			vn_p->v_type = VLNK;
 			break;
 		case	DEV_DIR:
 			if(dnp->by.Dir.parent == dnp)

sys/miscfs/devfs/devfs_vnops.c

@@ -1,7 +1,7 @@
 /*
  *  Written by Julian Elischer (julian@DIALix.oz.au)
  *
- *	$Header: /home/ncvs/src/sys/miscfs/devfs/devfs_vnops.c,v 1.20 1996/04/07 01:15:02 joerg Exp $
+ *	$Header: /home/ncvs/src/sys/miscfs/devfs/devfs_vnops.c,v 1.21 1996/06/12 05:08:34 gpalmer Exp $
  *
  * symlinks can wait 'til later.
  */
@@ -102,7 +102,7 @@ DBPRINT(("lookup\n"));
 	/*
 	 * Check accessiblity of directory.
 	 */
-	if (dir_node->type != DEV_DIR)
+	if (dir_node->type != DEV_DIR) /* XXX or symlink? */
 	{
 		return (ENOTDIR);
 	}
@@ -272,7 +272,7 @@ DBPRINT(("MKACCESS "));
 		if ((dir_node->mode & ISVTX) &&
 		    cnp->cn_cred->cr_uid != 0 &&
 		    cnp->cn_cred->cr_uid != dir_node->uid &&
-		    new_node->uid != cnp->cn_cred->cr_uid) {
+		    cnp->cn_cred->cr_uid != new_node->uid) {
 			VOP_UNLOCK((*result_vnode));
 			return (EPERM);
 		}
@@ -974,8 +974,7 @@ DBPRINT(("link\n"));
 	/*
 	 * Check we are doing legal things WRT the new flags
 	 */
-	if ((fp->flags & (IMMUTABLE | APPEND))
+	if (fp->flags & (IMMUTABLE | APPEND)) {
-	  || (tdp->flags & APPEND) /*XXX eh?*/ ) {
 		error = EPERM;
 		goto abortit;
 	}
@@ -1101,7 +1100,6 @@ devfs_rename(struct vop_rename_args *ap)
 	 */
 	if ((tp && (tp->flags & (IMMUTABLE | APPEND)))
 	  || (fp->flags & (IMMUTABLE | APPEND))
-	  || (tdp->flags & APPEND) /*XXX eh?*/
 	  || (fdp->flags & APPEND)) {
 		error = EPERM;
 		goto abortit;
@@ -1264,6 +1262,7 @@ devfs_rmdir(struct vop_rmdir_args *ap)
 DBPRINT(("rmdir\n"));
 	return 0;
 }
+#endif
 
 static int
 devfs_symlink(struct vop_symlink_args *ap)
@@ -1275,10 +1274,27 @@ devfs_symlink(struct vop_symlink_args *ap)
                 char *a_target;
         } */
 {
-	return EINVAL;
+	int err;
+	dn_p dnp;
+	union typeinfo by;
+	devnm_p nm_p;
+	struct vnode *vp;
+
 DBPRINT(("symlink\n"));
+	if(err = devfs_vntodn(ap->a_dvp,&dnp)) {
+		return err;
+	}
+		
+	by.Slnk.name = ap->a_target;
+	by.Slnk.namelen = strlen(ap->a_target);
+	dev_add_entry(	ap->a_cnp->cn_nameptr, dnp, DEV_SLNK, &by, &nm_p);
+	if(err = devfs_dntovn(nm_p->dnp,&vp) ) {
+		return err;
+	}
+	*ap->a_vpp = vp;
+	VOP_SETATTR(vp, ap->a_vap, ap->a_cnp->cn_cred, ap->a_cnp->cn_proc);
+	return 0;
 }
-#endif
 
 /*
  * Vnode op for readdir
@@ -1389,7 +1405,6 @@ DBPRINT(("readdir\n"));
 
 /*
  */
-#ifdef notyet
 static int
 devfs_readlink(struct vop_readlink_args *ap)
         /*struct vop_readlink_args {
@@ -1398,10 +1413,26 @@ devfs_readlink(struct vop_readlink_args *ap)
                 struct ucred *a_cred;
         } */
 {
+	struct vnode *vp = ap->a_vp;
+	struct uio *uio = ap->a_uio;
+	dn_p lnk_node;
+	int error = 0;
+
+
 DBPRINT(("readlink\n"));
-	return 0;
+/*  set up refs to dir */
+	if (error = devfs_vntodn(vp,&lnk_node))
+		return error;
+	if(lnk_node->type != DEV_SLNK)
+		return(EINVAL);
+	if (error = VOP_ACCESS(vp, VREAD, ap->a_cred, NULL)) { /* XXX */
+		return error;
+	}
+	error = uiomove(lnk_node->by.Slnk.name, lnk_node->by.Slnk.namelen, uio);
+	return error;
 }
 
+#ifdef notyet
 static int
 devfs_abortop(struct vop_abortop_args *ap)
         /*struct vop_abortop_args {
@@ -1638,9 +1669,11 @@ devfs_dropvnode(dn_p dnp)
 #define devfs_seek ((int (*) __P((struct  vop_seek_args *)))nullop)
 #define devfs_mkdir ((int (*) __P((struct  vop_mkdir_args *)))devfs_enotsupp)
 #define devfs_rmdir ((int (*) __P((struct  vop_rmdir_args *)))devfs_enotsupp)
+/*
 #define devfs_symlink ((int (*) __P((struct vop_symlink_args *)))devfs_enotsupp)
 #define devfs_readlink \
 	((int (*) __P((struct  vop_readlink_args *)))devfs_enotsupp)
+*/
 #define devfs_abortop ((int (*) __P((struct  vop_abortop_args *)))nullop)
 #define devfs_lock ((int (*) __P((struct  vop_lock_args *)))nullop)
 #define devfs_unlock ((int (*) __P((struct  vop_unlock_args *)))nullop)
@@ -1775,7 +1808,7 @@ static struct vnodeopv_entry_desc dev_spec_vnodeop_entries[] = {
 	{ &vop_rename_desc, (vop_t *)spec_rename },	/* rename */
 	{ &vop_mkdir_desc, (vop_t *)spec_mkdir },	/* mkdir */
 	{ &vop_rmdir_desc, (vop_t *)spec_rmdir },	/* rmdir */
-	{ &vop_symlink_desc, (vop_t *)spec_symlink },	/* symlink */
+	{ &vop_symlink_desc, (vop_t *)devfs_symlink },	/* symlink */
 	{ &vop_readdir_desc, (vop_t *)spec_readdir },	/* readdir */
 	{ &vop_readlink_desc, (vop_t *)spec_readlink },	/* readlink */
 	{ &vop_abortop_desc, (vop_t *)spec_abortop },	/* abortop */